1. Field of the Invention
The present invention relates to a wireless terminal device for use in a broadband wireless access system (BWA) and, more particularly, it relates to a wireless terminal device which maps a quality of service (QoS: quality securing) level of Layer 2 designated by a communication protocol and a content of a session description protocol (SDP: a protocol in which information on a session is described).
2. Description of the Related Art
It is to be noted that a QoS is a service function of reserving a band for specific communication to secure a fixed communication quality in a network.
Moreover, an SDP is specifically a protocol which depicts information on a session between terminals to exchange information necessary for transmitting/receiving a video or audio signal.
A wireless terminal device for a broadband wireless access system is manufactured according to IEEE802.16e standard of Non-Patent Documents 1 and 2 described hereinafter.
However, in the IEEE802.16e standard, as shown in FIG. 2, the standard is regulated only up to Layer 2. That is, the QoS in Layer 2 between the wireless terminal device for a BWA and a wireless base station for the BWA is regulated by the IEEE802.16e standard, but a mapping method of the QoS of an application of the wireless terminal device and the QoS of Layer 2 is not regulated.
Moreover, the QoS in a wire zone of the wireless base station in the whole network shown in FIG. 1 is not regulated. Therefore, the QoS in end-to-end (a zone from the BWA wireless terminal device to a phone for voice over IP in FIG. 1) cannot be ensured.
Furthermore, at present, on a wire core networks side, development of the next generation network (NGN) steadily progresses, and as disclosed in Non-Patent Document 4 described later, it is determined that the QoS is controlled by using the SDP disclosed in Non-Patent Document 3, but Non-Patent Document 4 does not disclose a relation with respect to the QoS level of the IEEE802.16e standard of Non-Patent Documents 1 and 2.
Therefore, when IEEE802.16e is used in an access system of the next generation network of Non-Patent Document 4, the QoS level on the next generation network side shown in FIG. 11 needs to be combined with the QoS of a zone (a zone between the wireless base station and the wireless terminal device for the BWA) in IEEE802.16e.
Moreover, when communication is started from the wireless terminal device for the BWA, the application in the terminal device needs to clearly determine the QoS of the wireless zone in the BWA, thereby operating the QoS in the wireless zone for the BWA.
To solve the above problem, as in Patent Document 1, there is suggested a method of disposing a policy server in a core network and disposing an application QoS function corresponding to the QoS of the policy server in the wireless terminal device for the BWA.    [Patent Document 1] US2007/0255793 A1, “METHOD FOR PROVIDING SERVICE BETWEEN HETEROGENEOUS NETWORK”    [Non-Patent Document 1] IEEE Std 802.16-2004, Part 16: Air Interface for Fixed Broadband Wireless Access Systems    [Non-Patent Document 2] IEEE Std 802.16e-2005 and IEEE Std 802.16-2004/Corl-2005, Part 16: Air Interface for Broadband Wireless Access Systems, Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1    [Non-Patent Document 3] IETF RFC4566 “SDP: Session Description Protocol”    [Non-Patent Document 4] Next Generation Network Interface Data (IP Communication Network/LAN type Communication Network)-Network-Network Interface (NNI)-Appendix 2: IP Transport Specifications